1. Field of the Invention
This invention relates to medical devices and, more particularly to novel apparatus and methods for soft tissue repair.
2. Background
Soft tissue of the human body, and more particularly the tendons of the hands and feet, are occasionally exposed to laceration and rupture. Repair of lacerated or ruptured tendons or other soft tissues is often complicated. Unless immobilized, tendons and other soft tissues of the body are typically under tensile loads of one amount or another. Such tensile loads on tendons tend to complicate the repair of tendons and other soft tissues. Tendons also tend to heal slowly. Tendons often receive a very limited supply of blood. It has been found that tendons receive most of their nutrition by diffusion via the synovial fluid. The diffusion process is slow and does not promote rapid healing of damaged tendon tissue. Furthermore, research has shown that tendons heal with a higher tensile strength and improved gliding ability when they are mobilized early and often during the healing process. When tendons are mobilized, however, they are exposed to tensile loads, which may rupture a repair made using current techniques.
An effective soft tissue repair must, therefore, simultaneously hold the severed ends together, support the tensile loads that are required for mobilization, and allow the nutrient fluid access to the soft tissue to provide the nutrition needed for healing.
Current suture methods have been found lacking. If a suture of sufficient strength to support the tensile loads of mobilization is used, the suture typically pulls through the soft tissue. If a thinner suture is used to prevent tear through, the suture itself is often unable to support the tensile loads associated with mobilization.
Tendon clips have been introduced to grip the tendon ends and hold them together. Tendons clips have several drawbacks. They are typically circumferential devices and significantly restrict the flow of nutrients to the tendon cells, possibly causing necrosis of the tendon. As the tendon negotiates around pulleys and corners and through synovial sheaths, the tendon clip may cut into the fibers of the tendon. The typical tube shape tendon clips make a relatively inflexible restraint to the naturally flexible tendon, again increasing the likelihood of damaging the tendon. The circumferential nature increases the bulk of the device, limiting the possible areas of application. Furthermore, tendon clips require multiple sizes, thus increasing manufacture costs and increasing the time consumed in finding the best fit.
Some current tendon clips require crimping, creating the possibility of crushing or otherwise damaging the tendon. Additionally, crimping requires special pliers, which, in many instances, may not be admitted into the confined spaces where tendons frequently are injured.
Current tendon grafting methods have also been found lacking. Grafts are often required when an injury has destroyed a significant length of tendon. In many cases, a graft can not be installed immediately upon need. Typically, a synthetic rod is placed in the location where the graft is needed. The rod maintains the spacing and passageway while the surrounding tissue heals. After the surrounding environment has healed, a surgeon removes the rod and inserts the graft. This process requires two surgeries, greatly increasing the cost of the procedure. Additionally, the patient is without the use of his/her full physical capabilities for six to eight weeks per surgery. A simple grafting procedure is needed which will allow the graft to be completed in a single surgery, thus reducing costs and patient down time.
In view of the foregoing, it would be an advancement in the art to produce an apparatus and method for securing a soft tissue repair site while simultaneously preventing tear through, allowing for early and relatively complete mobilization of the joints associated with the repaired tissue, and minimizing the soft tissue area that can not be accessed by the nutrient fluids. Such an apparatus would minimize the need for expensive splints and costly occupational therapy used to mobilize repaired soft tissues without exceeding the limited forces supported by current repairs methods.
In view of the foregoing, it is a principal object of the present invention to provide a soft tissue repair of sufficient strength to allow an immediate and active mobilization of the soft tissue.
It is also an object of the present invention to provide a repair that will allow smooth motion of the repaired soft tissue through tight anatomical passageways.
It is a further object of the present invention to provide a repair that will maximize the surface area of the soft tissue that may be exposed to nutrient fluids that aid in the healing process.
It is another object of the present invention to provide a repair sufficiently flexible to allow the repair site to bend and move as it passes around pulleys and other structures within the body.
It is another object of the present invention to provide a repair that may be easily implemented by a variety of medical specialties, including without limitation general orthopaedists, plastic surgeons, and hand surgeons.
The foregoing objects and benefits of the present invention will become clearer through an examination of the drawings, description of the drawings, description of embodiments, and claims which follow.
Consistent with the foregoing objects, and in accordance with the invention as embodied and broadly described herein, an apparatus and method are disclosed, in suitable detail to enable one of ordinary skill in the art to make and use the invention.
In certain embodiments an apparatus and method in accordance with the present invention may include an anchor configured to engage soft tissue of the body. The anchor may comprise a plate formed to have longitudinal, lateral, and transverse directions substantially orthogonal to one another. The plate may have a plurality of apertures and a top and a bottom surface defined by the transverse direction. Selected apertures of the plurality of apertures may be configured to receive sutures therethrough. Other apertures of the plurality of apertures may provide access for a nutritional fluid, such as synovial fluid, to the soft tissue.
In selected embodiments, a plurality of teeth may extend generally transversely from the bottom surface of the plate. The teeth may penetrate the soft tissue to substantially prevent longitudinal motion between the anchor and the soft tissue. The number and geometry of the teeth may be selected to provide strength of engagement of the anchor to the soft tissue while minimizing the risk of tearing and injury to the soft tissue.
A securement mechanism may transversely secure the anchor to the soft tissue. The securement mechanism may be a circumferential band, a suture, or any other suitable mechanism capable of transversely securing the anchor to the soft tissue without covering significant portions of the soft tissue surface. In one presently preferred embodiment, the securement mechanism comprises a suture secured to the plate, passing transversely through the soft tissue, passing over some distance on the surface of the soft tissue, reentering the soft tissue to pass transversely therethrough, and securing again to the anchor.
In certain embodiments, the suture may make several passes transversely through the soft tissue. The number of passes may be selected to provide both transverse and longitudinal securement of the anchor to the soft tissue, thus eliminating the need for the plurality of teeth.
When the anchor is properly transversely and longitudinally secured to the soft tissue, the anchor provides a xe2x80x9chandlexe2x80x9d on the soft tissue. The xe2x80x9chandlexe2x80x9d enables a surgeon to position the severed end or surface of the soft tissue against any desired surface. The anchor distributes whatever loads are applied to it over a relatively large area of the soft tissue. Such distribution of loads prevents any particular point or location in the soft tissue from supporting all, or significant portions, of the applied loads. Thus, the anchor may greatly reduce the risk of tearing of the soft tissue and subsequent repair failure even while supporting significant mobilization loads.
The opposing surface to which the soft tissue may be abutted may be a similar or dissimilar tissue. In selected embodiments, the soft tissue may be a first severed tendon. The first severed tendon end may be abutted against a second tendon having a similarly severed end. In such a situation, it is typically desirable to provide at least one anchor to engage both tendons. A longitudinal connector may connect at least one anchor on the first tendon to at least one anchor on the second tendon. The longitudinal connector, in cooperation with the anchors, abuts the severed surfaces of the first and second tendons creating a repair site. Additionally, the longitudinal connector supports whatever tensile loads of mobilization may be applied across the repair site, thus preventing the repair site from being pulled apart while the soft tissue heals. Several stitches may be incorporated at the repair site to aid the repair in maintaining a proper alignment.
In certain embodiments, the soft tissue may again be a first severed tendon. The severed first end may be abutted against a first end of a graft tendon segment. A second severed tendon end may be abutted against the second end of the graft tendon. At least one anchor may engage the first severed tendon end and at least one anchor may engage the second severed tendon end. A longitudinal securement mechanism may extend from an anchor secured to the first severed tendon to an anchor secured to the second severed tendon end. The longitudinal securement mechanism may extend alongside or through the graft tendon segment. In such a configuration, the repair in accordance with the present invention provides a method of securing both repair sites (both ends of the graft) with a single repair.
If the graft segment is comparatively long, it may desirable to provide a repair for each end of the graft. In such a configuration, longitudinal securement mechanisms may simply extend from an anchor secured to the first severed tendon end to an anchor secured to the first end of the graft segment. A similar longitudinal securement mechanism may be provided for the other end of the graft.
In other embodiments in accordance with the present invention, the repair may abut a soft tissue, such as a tendon, against a dissimilar tissue, such as a bone. In such a configuration, at least one anchor may engage a first tendon end. A longitudinal securement mechanism may engage an anchor secured to the tendon and extend to a tie-off region. The tie-off region may provide a stop to which the longitudinal securement mechanism may be secured to maintain the tendon end against the bone.
The longitudinal securement may be any suitable mechanism that provides the proper balance of tensile strength and flexibility. The proper balance may vary from repair to repair. The longitudinal securement mechanism must also allow for securement to the anchors. In one embodiment, the longitudinal securement mechanism may be a suture of a size selected to provide the necessary tensile strength.